An example of a conventional paint roller frame is shown in FIG. 1 of the accompanying drawings. The roller frame 1 includes a cage 2 having a plurality of resiliently deformable metal bars 3 spaced about an axis of rotation corresponding to a central shaft 4. The ends of the bars 3 are secured to a pair of end supports 5, 6 which serve to hold the bars in fixed circumferential positions and allow the bars to flex inwardly towards the shaft 4. The end support 5 at the free end of the cage 2 is cylindrical in shape to enable a roller cover (not shown) to slide over this end support and then be pushed onto, and subsequently gripped by, the bars 3. The other end support 6 is also cylindrical in shape but includes an end stop 7 to limit axial movement of the roller cover on the cage 2. The end supports 5 and 6 freely rotate about the central shaft 4 to allow free rotation of the cage 2 and the roller cover relative to the roller frame 1. An arm 8 connects the shaft 4 to a handle 9.
A conventional roller cover, also referred to as a roller sleeve, includes a cylindrical core which is covered with an absorbent material such as a napped fibre. In the context of paint roller covers, the size of a roller cover (“large”, “small”, etc.) refers to the diameter of its core rather than to its length. In Australia, for example, conventional paint roller covers have a cylindrical core with a nominal internal diameter of 38 mm. But typical samples may range in size between 37 mm and 39 mm depending on the manufacturer. It is for this reason that paint roller frames are generally provided with a resilient cage structure of the type described above.
Paint roller covers also come in varying lengths, and frames with cages of corresponding lengths are provided for each roller cover length.
While 38 mm (1½ inch) is the nominal diameter of conventional paint roller covers in Australia, larger diameter covers are available in some countries. For example, covers of 45 mm (1¾ inch), 51 mm (2 inch), 57 mm (2¼ inch) and 64+mm (2½+ inch) have been found to be commercially available. Larger diameter covers have a number of benefits including:
a) a larger rolling diameter, resulting in smoother operation for the user when applying paint and making it easier to push the roller along a surface;
b) smoother paint finish;
c) greater area of absorbent material around the circumference of the roller cover, whereby the larger cover area holds more paint;
d) with a thicker nap, or pile, of absorbent material there is an increase in the amount of paint which can be picked up and held by the cover, again resulting in more paint on the roller; and
e) during painting, there is less requirement to “load” the roller, for example when painting a room, thereby minimising the need for the user to bend over to load paint from a tray.
With these benefits in mind, it would be desirable to provide some way to install a large diameter cover on a conventional frame intended for smaller diameter covers. The present invention is accordingly directed to meeting this need.